I don't understand the proposal. Are you trying to:
A) Keep the registration (uniqueness), whois (at least pointers), and
reverse DNS (again, at least pointers) for the legacy address blocks in
the ARIN region under ARIN control? (In which case I don't see what
anyone would be "opting out" of)
B) Remove the legacy address blocks from ARIN control and transfer them
to a new entity? (In which case I think you need to be operating under
ICANN ICP-2 with regard to the formation of this new entity, and it
isn't appropriate for the ARIN PDP)
C) Remove the legacy address blocks from ARIN control and NOT transfer
them to a new entity? (In which case I'm not sure where you'd go,
because ICANN clearly has the assumption that a single RIR will have
responsibility for the block(s))
Matthew Kaufman